A Study to Evaluate the Safety and Immunogenicity of Ad5-vector Based Vaccine Against Coronavirus Variants in Adults (≥18 Years) Immunized With 2 Doses of mRNA Vaccines Plus One Dose of Booster AZD1222 Vaccine

A Multicenter, Randomized, and Observer-blind Clinical Trial to Evaluate the Safety and Immunogenicity of Ad5-based COVID-19 Vaccine Against Coronavirus Variants in Adults (≥ 18 Years) Who Have Been Immunized With 2 Doses of mRNA Vaccines Plus One Dose of Booster AZD1222 Vaccine

Status

Withdrawn

Phases

Phase 3

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT05442684

Enrollment

Registered

2022-07-05

Start date

2022-11-30

Completion date

2023-06-30

Last updated

2023-06-18

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

COVID-19

Brief summary

Subjects who have completed the primary mRNA vaccine immunizations and the 1st booster AZD1222 immunization for more than 6 months will be randomized to receive a 2nd booster dose of Ad5-nCoV/O, Ad5-nCoV/O-IH or mRNA-based COVID-19 vaccine in a ratio of 2:2:1.

Detailed description

This is a multicenter, randomized, observer-blind, and parallel-controlled clinical study to evaluate the immune responses and safety profiles in adults (≥ 18 years) receiving investigational products (intramuscular injection or nebulized inhalation) ≥ 180 days after the immunization of 2 doses of BNT162b2 vaccines plus one dose of booster AZD1222 vaccine. This study will enroll about 30% participants aged 60 years and above. Subjects who have completed the primary mRNA vaccine immunizations and the 1st booster AZD1222 immunization for more than 6 months will be randomized to receive a 2nd booster dose of Ad5-nCoV/O, Ad5-nCoV/O-IH or mRNA-based COVID-19 vaccine in a ratio of 2:2:1.

Interventions

BIOLOGICALBivalent Recombinant COVID-19 Vaccine (Adenovirus Type 5 Vector)

Subjects who have completed the primary mRNA vaccine immunizations and the 1st booster AZD1222 immunization for more than 6 months will be randomized to receive a 2nd booster dose of Ad5-nCoV/O

BIOLOGICALBivalent Recombinant COVID-19 Vaccine (Adenovirus Type 5 Vector) for Inhalation

Subjects who have completed the primary mRNA vaccine immunizations and the 1st booster AZD1222 immunization for more than 6 months will be randomized to receive a 2nd booster dose of Ad5-nCoV/O-IH

BIOLOGICALmRNA-based COVID-19 vaccine

Study design

Allocation

RANDOMIZED

Intervention model

PARALLEL

Primary purpose

PREVENTION

Masking

SINGLE (Investigator)

Masking description

observer-blind clinical trial

Intervention model description

Eligibility

Sex/Gender

ALL

Age

18 Years to No maximum

Healthy volunteers

Yes

Inclusion criteria

1. Participants aged 18 years and above at the time of screening. 2. Received the 1st booster vaccination at least 180 days earlier. 3. Agree to attend all visits and sign the written informed consent form.

Exclusion criteria

1. Have a history of seizures, epilepsy, encephalopathy, psychosis. 2. History of severe anaphylaxis or allergy to any vaccine component. 3. Positive urine pregnancy test result, pregnant, lactating women. 4. Medical history of Guillain-Barré syndrome. 5. Have had asthma attacks within 2 years. 6. Have severe nasal or oral diseases, such as rhinitis (sinusitis), allergic rhinitis, oral ulcer, throat swelling, etc. 7. Bleeding disorder (e.g. protein S or factor deficiency, coagulopathy or platelet disorder). 8. Have chronic systematic infection or chronic obstructive pulmonary disease (COPD), etc. 9. Administration of immunoglobulins and/or any blood products within three months prior to the planned administration of the vaccine candidate. 10. Current diagnosis or receiving treatment for tuberculosis or cancer. 11. History of SARS-CoV-2 infection for less than 3 months. 12. Received or plan to receive any vaccines (licensed or investigational), within 14 days before and after study vaccination. 13. Have an axillary temperature of \> 37.0℃. 14. Any other significant diseases, disorders or findings which may significantly increase the risk to the volunteer because of participation in the study, and affect the ability of the volunteer to participate in the study or impair interpretation of the study data.

Design outcomes

Primary

Measure	Time frame	Description
Immunogenicity of Ad5-nCoV/O or Ad5-nCoV/O-IH versus BNT162b2 as the 2nd booster dose.	Day 28 post vaccination	The geometric mean titers (GMT) of anti-Omicron pseudovirus neutralizing antibody on Day 28 post vaccination in all participants

Secondary

Measure	Time frame	Description
The incidence of AR and AE	within 28 days post vaccination	The incidence of ARs/adverse events (AEs) within 28 days post vaccination.
Incidence of SAE	within 12 months post vaccination	The incidence of serious adverse events (SAEs) and adverse events of special interest (AESIs) within 12 months post vaccination.
Immunogenicity of pseudovirus neutralizing antibody	on Day 14 and Day 28 post-vaccination	The GMT, geometric mean increase fold (GMI) and sero-conversion rate (SCR) of anti-Omicron pseudovirus neutralizing antibody on Day 14 and Day 28 post-vaccination in all participants.
Immunogenicity of S-RBD IgG antibody	on Day 14 and Day 28 post-vaccination	The geometric mean concentration (GMC), GMI and SCR of anti-Omicron S-RBD IgG antibody on Day 14 and Day 28 post-vaccination in all participants.
Immunogenicity of S-RBD serum IgA antibody	on Day 14 and Day 28 post-vaccination	The GMT, GMI, and SCR of anti-Omicron S-RBD serum IgA antibody on Day 14 and Day 28 post-vaccination in all participants.
Virological confirmed COVID-19 cases	from Day 14 post-vaccination	The number of virological confirmed COVID-19 cases occurring from Day 14 post-vaccination in different vaccine groups.
Incidence of Adverse Reactions (ARs)	within 30 min post vaccination	The incidence of adverse reactions (ARs) within 30 min post vaccination.
Virological confirmed asymptomatic COVID-19 cases	from Day 14 post-vaccination	The number of virological confirmed asymptomatic COVID-19 cases occurring from Day 14 post-vaccination in different vaccine groups.
Immunogenicity of anti-Nucleocapsid antibody	before vaccination	The GMT of anti-Nucleocapsid antibody before vaccination
Immunogenicity of saliva secretory IgA (SIgA)	on Day 14 and Day 28 post-vaccination	The GMC, GMI, and SCR of saliva secretory IgA (SIgA) on Day 14 and Day 28 post-vaccination in participants of the immunogenicity subgroup.
The level and positive rate of interferon γ (IFN-γ)	on Day 14 and Day 28 after the 2nd booster dose	The level and positive rate of interferon γ (IFN-γ) on Day 14 and Day 28 after the 2nd booster dose.
The neutralizing antibody against other VOCs or emerging variant(s).	on Day 28	The neutralizing antibody on Day 28 against VOCs or other emerging variants.
Virological confirmed severe COVID-19 cases.	from Day 14 post-vaccination	The number of virological confirmed severe COVID-19 cases occurring from Day 14 post-vaccination in different vaccine groups.

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026